Chilean Sinovac trial leaders recommend third dose of COVID-19 vaccine

The leaders of the Chilean late-stage human trial of the CoronaVac COVID-19 vaccine developed by Chinese pharmaceutical firm Sinovac on Thursday recommended a third dose of the jab, saying studies of participants showed their protecting antibody levels were lower after six months.

The trial leaders said that an in vitro trial to determine the vaccine's effectiveness against the more contagious Delta strain of the virus showed a four-fold reduction in neutralizing effect against it, compared to a less severe, three-fold reduction previously reported by Chinese scientists.